Questions tagged [cfd]
questions about computational fluid dynamics
101 questions
0 votes
0 answers
42 views
Mountain bicycle rubber tires - Will I inhale fumes while riding very slowly in an urban environment? CFD experts based answer required
I recently bought new mountain bicycles. In fear of theft, I stored them a medium sized work room inside the apartment. After ~20 minutes the situation was unbearable. Even after opening all the ...
9 votes
4 answers
6k views
Why are all computer fan blades thin?
100% of all PC cooling fans from 90s to today, from 40mm to 200mm, from budget to most expensive high performance models, they all use thin blades. Why? Airplanes wings and propellers use more complex ...
- 309
1 vote
2 answers
451 views
Calculating Pressure Drop from Water Pipe Discharging to Atmosphere
I have an application at work where I am draining a water tank. The outlet valve is a flush mount, and I know the Cv value from manufacturer website. I can calculate the pressure drop through this ...
- 23
0 votes
0 answers
49 views
Boundary conditions for stratified thermal storage model with variable in- and outlet positions
I am working on a stratified thermal storage model for a vertical tank and I am having trouble defining the boundary conditions for the edge cells. All the models I could find online have the inlet at ...
-1 votes
2 answers
219 views
FreeCAD/OpenFOAM vs Paid CFD Software
I am a mechanical engineer who is dipping his toes in CFD for a work project, where we have an array of axial fans in a tower and we're trying to optimise the airflow (its actually two towers facing ...
0 votes
1 answer
142 views
Evaporation of water using a vacuum pump - COMSOL
I'm using COMSOL to simulate a system where liquid water is evaporated using a vacuum pump, but I am struggling to understand the mass transport process of vapor from the liquid-air interphase to the ...
0 votes
0 answers
208 views
Best Practice for Multiple Zones in ANSYS Design Modeler for a 3D Structured Mesh for Fluent Simulation
I am building a structured mesh in a rectangular domain to model the flow over a wing with impinging jets at the root over the surface in the spanwise direction. I've tried building unstructured ...
- 162
0 votes
1 answer
144 views
CFD numerical methods (FEA, FVM, FDM,…)
I just read the answer from this question and have a question please: What I read: Computational Fluid Dynamics (CFD) refers to the use of the numerical techniques to solve fluid dynamical problems. ...
- 1
0 votes
0 answers
80 views
Why does CFD over predict shockwave in comparison to wind tunnel?
I ran a CFD simulation of Mach=0.85 flow over an aerofoil and noted that my Cp (coefficient of pressure) plot over predicts the shockwave in comparison to experimental data? Can someone please explain ...
- 1
0 votes
0 answers
55 views
Thermal Undershooting In SLM Simulation on Ansys Fluent
I am creating a SLM simulation of basalt on Ansys Fluent. I have enabled laminar viscosity, solidification and melting, and the energy equation. The heat flux is applied to the top wall through the ...
0 votes
0 answers
48 views
Which, if any, CFD methods would be best for predicting performance of a sailboat?
I am interested in using a CFD simulator to calculate the performance potential of a sailboat. And not just a single boat, but of multiple boats of different configurations and hull shapes. If I know ...
- 101
0 votes
1 answer
86 views
Typical Runoff velocity values
I am computing runoff velocities for rainfall falling over an area using St-Venant 1D momentum equation. I wanted to have some idea if my computed velocities are within a reasonable range of what one ...
1 vote
0 answers
60 views
Why is the turbulent kinetic energy $k=\overline{v_1'^2}+\overline{v_2'^2}+\overline{v_3'^2}$ even in 2D cases?
I'm writing an essay which partly includes writing about the Reynolds stress model where the dissipation term $\varepsilon_{ij}$ is assumed to be isotropic (since dissipation mostly occurs at small ...
- 11
0 votes
1 answer
117 views
In Ansys ICEM CFD, what do these "cube" symbols on the midpoint of block edges mean?
When I was meshing a helical coil, I've noticed these "cube" symbols located at the midpoint of a the block's edges: Blocks with these symbols tend to have a lot of strange/unpredictable ...
0 votes
0 answers
65 views
approximate equation for temperature drop near wall in contact with fluid
I am concerned about the following problem and so far I am not able to find a solution. Let us consider an environment at a temperature $T_a$ and the inner surface of a not insulating wall in contact ...
- 101